1. Field of the Invention
The present invention is directed to a process and apparatus for adjusting an electrical characteristic of a component of an electrical network, which consists of a stack of layers or foils, which are secured together and include at least one synthetic carrier foil with a metal layer and a thermoplastic cover foil, and has connecting wires which are fused through the outer cover foil are welded to the desired portions or spots of a metal layer.
2. Prior Art
Electrical networks having one or more electrical components are disclosed in U.S. Pat. No. 3,913,224 which is based on German Offenlegungsschrift No. 22 47 279. As disclosed in this patent, the network is composed of a plurality of synthetic foils or layers which are arranged in the stack and secured together. The stack has one or more synthetic carrier foils which are provided with a metal layer on either one or both sides and a cover foil of thermoplastic material. To form a connection with the components formed in the stack, a connecting wire is fused through the cover foil and any inner foils until it contacts and is welded to a desired portion of a metal layer of a component. A network of this type can be favorably produced in large numbers in an economical fashion. The stack may be formed of a plurality of different networks, which are subsequently divided up into the individual networks if desired.
In accordance with the present practice, an electrical component particularly a resistor, which has been applied to one of the synthetic foils in the form of a thin layer, is adjusted or trimmed to the desired theoretical value before the individual foils are assembled into the stack to form the network. During the following processing steps, changes may occur in the electrical characteristics of the component and these changes necessitate a final checking of the completed network. Due to changes occurring in the electrical characteristics of the component during formation of the network, the electrical characteristics may fall outside of the permitted tolerance. Since an adjustment of the characteristics of the components is not possible after forming the network, those networks having characteristics outside of the tolerance range must be scrapped or rejected.